1. Field
The disclosed concept pertains generally to acoustic noise induced by electrical conductivity faults and, more particularly, to acoustic sensor systems for electrical distribution systems.
2. Background Information
There is no known cost effective technology and product to detect loose electrical connections in electrical distribution systems. An infrared imaging scan has been widely used to find such loose electrical connections, but this does not provide continuous (e.g., “24-7” or 24 hours a day, seven days a week) detection and monitoring, is limited to detecting only joints within view, and exposes the operator to potentially hazardous conditions.
Other known products employ temperature sensing at each electrical joint. However, this has not been widely adopted due to cost.
It is believed to be almost impossible to extract a loose electrical connection signature from both current and voltage due to the relatively small voltage drop across a loose electrical connection (except when this escalates into a major arc fault or arc flash event) except by monitoring voltage drops at each electrical connection.
U.S. Pat. No. 7,148,696 discloses that an acoustic signature is generated by an arc fault or a glowing contact. An acoustic sensor “listens” directly to signature noise generated by a fault, no matter what type of electrical load is present or in what kind of environment in which the fault is generated. The acoustic noise generated by an arc fault or a glowing contact has an acoustic signal at one or more specific wavelengths that is (are) directly related to either the basic characteristics of, for example, the arc and its resonance frequency or the AC power source modulated frequency and its harmonics. The acoustic signal of an arc fault is detected by an acoustic sensor. A resulting trip signal is sent to a trip mechanism to, for example, trip open separable contacts, in order to interrupt the arc fault.
There is a need for a cost effective technology and product to effectively detect electrical conductivity faults, such as loose electrical connections, at their earliest stage in order to prevent potential equipment damage and/or personal injury.
There is room for improvement in acoustic sensor systems.
There is also room for improvement in the detection of electrical conductivity faults.